RNF213 and familial isolated congenital asplenia: A substantial proportion of patients (28.4%, 19 of 67 patients) in whom ICAS was confirmed by the presence of focal eccentric plaque on HR-MRI and absence of basal collaterals (moyamoya vessels) on conventional angiography had the RNF213 variant (Fig 1); 25.2% (33 of 131 patients) of the ICAS group who had focal eccentric plaques without negative remodeling on the relevant stenotic segment on HR-MRI had this variant.